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Tuesday, November 17, 2009

Progression to daily marijuana use in adolescence may hasten the onset of symptoms leading up to psychosis, an Emory study finds. The study was published in the November issue of the American Journal of Psychiatry.

The researchers analyzed data from 109 hospitalized patients who were experiencing their first psychotic episode. The results showed that patients who had a history of using marijuana, or cannabis, and increased to daily pot smoking experienced both psychotic and pre-psychotic symptoms at earlier ages.

"We were surprised that it wasn't just whether or not they used cannabis in adolescence that predicted the age of onset, rather it was how quickly they progressed to becoming a daily cannabis user that was the stronger predictor," says Michael Compton, lead author and assistant professor of psychiatry in the Emory School of Medicine.

The Emory study focused on what is known as the prodromal period, when a person has symptoms such as unusual sensory experiences, which are often precursors to frank hallucinations and delusions. “The prodromal period is especially important because it’s considered to be a critical time for preventive intervention,” says Elaine Walker, a co-investigator of the study and professor of psychology and neuroscience at Emory.